Reuben's Home Inspection Blog

“You just cost me a lot of money!”

April 26th, 2011 | 4 comments

Do you remember the telephone game? You’d get a bunch of kids in a circle, and the first kid would whisper a phrase in the next kids ear, and then that kid would whisper it to the next, and so on. Once the last person heard the message, they’d say aloud what they heard, and everyone would have a great laugh because the message was never even close to what the first person said.

While this is all great fun for kids, it’s frustrating when it happens in the real estate world… especially when it happens on purpose. If you read my blogs with any regularity, you already know that I’m passionate about my work and I stand behind my inspection reports. I welcome challenges to my calls, and I stand behind them… but sometimes I don’t get the chance.

Some time ago, I inspected a home with a 23 year old Trane furnace where I was able to remove the back panel to get a clear look at the heat exchanger. Many older Trane and GE furnaces have these removable panels which makes inspecting the heat exchanger a piece of cake. I found obvious cracks in every single port of the heat exchanger, so I told my client to replace the furnace, and I even included photos of the cracked heat exchanger in my report. This should have been a no-brainer furnace replacement, but it didn’t work out that way.

Back of GE Furnace Cracked Heat Exchanger

Two days later I received this voicemail – the choppy parts are where I removed the agent’s name, house address, and the name of the HVAC contractor:

Click here to hear the voicemail – You just cost me a lot of money

TroyI think I had steam coming out of my ears after I listened to that message. Who told the owner to hire a heating contractor to “inspect my comments”? Certainly not me. Weren’t my photos of the cracked heat exchanger good enough? Above all, why would a contractor say the furnace was perfectly fine? I don’t know of any contractor that would use language like that about a 23 year old furnace. The best thing I’ve ever heard a heating contractor say about a 23 year old furnace is “I can’t find any problems with it.” This didn’t make any sense.

I had to get to the bottom of this, so I waited several hours until I was calm enough to speak in a civil manner, and I finally called the listing agent back. I got the name of the heating contractor and called him to chat about the furnace. The contractor sheepishly admitted that he wasn’t aware that this furnace had a removable back panel, so he never found the cracks.

I asked the contractor why he would have said that there were “no cracks at all” and that there was “nothing wrong with the furnace, at all”. Can you guess what he told me? He said he never said that. The contractor told the homeowner that the furnace was heavily rusted, 23 years old, and most likely did have a cracked heat exchanger, but he couldn’t find any cracks.

I called the listing agent back and told him what the contractor told me. The listing agent apologized and said he wasn’t even the person that talked to the contractor in the first place; he was just repeating what the owner told him. Huh. There’s the telephone game. I told the agent that I didn’t envy his job.

If you want the full story, sometimes you have to just go to the source. To this day, I’d still love to know exactly what that homeowner told his agent.

Reuben Saltzman, Structure Tech Home Inspections – EmailMinnesota Home Inspections

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How Serious Is A Cracked Heat Exchanger?

March 2nd, 2010 | 1 comment

It’s an industry standard: if a furnace has a cracked heat exchanger, it gets replaced.  The American Gas Association has even put this in writing – they say “Any visible crack or hole is reason for requiring replacement of the heat exchanger or furnace.”  When I inspect a furnace and I find a cracked heat exchanger (and I find a lot of them), I always say to replace it.

So what’s the big deal with cracks or holes?  The concern is that a cracked heat exchanger could allow exhaust gas from the furnace to contaminate the household air with carbon monoxide.   In order for this to happen, the furnace must be producing high levels of carbon monoxide AND the exhaust gas must be mixing with the household air.  For a good example of a hazardous heat exchanger, check out the photo below showing a large rust hole in the heat exchanger of this high-efficiency furnace that was only ten years old.

Rust Hole in Heat Exchanger

Cracks, on the other hand, I’m not so sure about.  With the majority of the cracked heat exchangers that I’ve seen, I’ve always been curious how the exhaust gas from the furnace could possibly leak out of those tiny cracks enough to contaminate the househouse air.  Of course, what I’m curious about doesn’t matter… but sometimes my curiosity gets the best of me, and I have to find out for myself.

So I did. I took home a furnace that had a cracked heat exchanger, and I removed the heat exchanger cell that had the largest cracks.  You can see the cracks for yourself below – click on any of the photos for a larger version.  This first photo shows the cracks as seen from inside the heat exchanger cell – this is what we saw during our inspection.

Cracked Heat Exchanger Inside

These next two photos show the cracks from the exterior, or blower side of the heat exchanger cell.  This part of the heat exchanger is usually not visible during the course of a home inspection.

Cracked Heat Exchanger Outside Cracked Heat Exchanger Outside 2

I wanted to see if water would leak through these cracks, so I doused the outside of the heat exchanger and looked inside for any signs of leakage.  Nothing.

I’ve heard that penetrating oil, such as WD40, will get through the cracks, so I tried that next.  Nothing.

Feeling pretty disappointed at this point and determined to get some results, I filled the heat exchanger with water.  I laughed like a mad scientist at what happened next.

Water Test on Heat Exchanger

Water began to leak out of the factory seam in about ten different places, but the crack never leaked.

Why does this tiny crack mean the furnace should be replaced?  I’ve heard that when heat exchangers get very hot, the metal expands and the cracks open up, allowing air to leak in to or out of the heat exchanger.  Just because my test didn’t allow any water to leak doesn’t mean that this furnace was safe, and it doesn’t mean that a different furnace will behave the same way… but I sure found it amusing.

Maybe I need to get out more.


Reuben Saltzman, Structure Tech Home Inspections – Email – Twin Cities Home Inspector

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Furnace Certifications Might Be Useless

October 6th, 2009 | 9 comments

I used to recommend furnace certifications all the time, but I don’t do it any more.   Heresy you say?  No, I have good reason not to.  T’his all started several years ago when I meant to write a blog about what’s involved in furnace certifications and who does them, so I contacted 40 local HVAC contractors.

I was quite surprised at most of the responses I received.

An Easy Call

Cracked Heat Exchanger

When I inspect a furnace and I find a serious problem, such as a cracked heat exchanger, it’s easy for me to tell my clients what to do: replace the furnace.   The photo above shows a cracked heat exchanger on a furnace, looking at it from the back – this GE furnace had a removable back panel that gave me a good look at the back of the heat exchanger, and made finding cracks very easy.

Cracked Heat Exchanger

Cracked Heat Exchanger

The Grey Area Unfortunately, diagnosing a cracked heat exchanger is almost always a difficult if not impossible task.  Home inspectors are usually only able to see the burner side of the heat exchanger, and this area is often dirty and rusty, making cracks very difficult to find.  The photo at right shows a crack as seen from the inside of a heat exchanger, and it’s one of the most obvious heat exchanger cracks I’ve ever seen – yet it’s still tough to see.  Home inspection standards disclaim the inspection of the heat exchanger just for this reason, but many home inspectors still do their best to look for problems.  

What Excellent HVAC Contractors Do  Many years ago, I attended a seminar put on by a very reputable HVAC firm, where the speaker talked about what was involved with a furnace ‘certification’, which was the type of inspection they would do when a home inspector suspected a problem.  The guy leading the class talked about using mirrors, borescopes, smoke bombs, leak seek tests, and basically dismantling a furnace to get a good look at the heat exchanger to check for cracks.  He assured us that if there was a crack to be found, they were happy to go out of their way to find it, and that’s what a furnace certification was all about.

What Other HVAC Contractors Do  To gather information for this blog, I contacted 40 different HVAC contractors.  The price for a furnace certification varied between $135 and $219, and almost every contractor said that a furnace certification consists of an Orsat test.  That’s it.  An Orsat test measures temperature, CO² and 0² in order to determine the efficiency of an appliance, and that’s about it.  Some of the more savvy heating contractors might use these numbers to know there is a serious problem… but an Orsat test will not determine the presence of a crack in a heat exchanger.   After making all of these phone calls and sending all of these emails, I don’t think I’ll ever recommend another furnace certification.  It’s just not enough.

Saint Louis Park has it right  In my humble opinion, the City of Saint Louis Park has had it right for a long time; when they do their Point-Of-Sale Evaluations, they automatically require a certification on furnaces over 20 years old, and they also require a smoke bomb or leak seek test, which is specifically designed to test for a cracked heat exchanger.  

Don’t Call CenterPoint  The local gas company, Centerpoint Energy, offers safety inspections of furnaces for far less than licensed heating contractors.  Can you guess why the price is so low?  Because it’s not a certification!  They won’t do certifications on furnaces, much less smoke bomb or leak seek tests.  They also won’t fill out a safety check form for Minneapolis or any other city.  Almost half the time I recommend a furnace certification, someone ends up calling the gas company instead, and to no surprise, the gas company says everything is fine.  I called CenterPoint to see how it was so easy for people to confuse a certification with a basic safety check, and I was quite surprised. Here’s how the conversation went:

Me: Hi, can I have my furnace inspected?

Centerpoint: Why, did an inspector suspect a problem with it, or are you selling your house?

Me: Yes, the people buying my house want to make sure it’s safe.

Centerpoint: I’m sorry, we don’t offer that type of service. You’ll need to contact a private HVAC contractor.

The gas company was very clear about not offering certifications or anything close to that.  So how does the local gas company show up at the majority of houses that I’m recommending certifications on?  It’s probably a communication problem.  I tell the buyer to get a certification, they tell their agent, that agent tells the seller’s agent, and the seller’s agent tells the seller.  The seller eventually hears “Get your furnace checked out”.

From now on, I’ll be recommending leak seek tests when I suspect a cracked heat exchanger.  One of the better companies that I contacted does certifications for $135, and they always do smoke bomb tests or leak seek tests when they suspect a problem.

Reuben Saltzman, Structure Tech Home Inspections – Email – Saint Louis Park Home Inspections

Houses Don’t Need C02 Detectors

January 17th, 2009 | 1 comment

There are many common misconceptions about furnaces, water heaters, and carbon monoxide that I hear repeated on a daily basis, and I’d like to clear a few of them up.

False: Carbon Monoxide is also called CO2.  Carbon Monoxide is CO. Carbon Dioxide is CO2.  (Mono = 1, Di = 2)

False: Cracked heat exchangers create CO.  CO is caused by incomplete combustion, period.  A cracked heat exchanger does not create CO.  A heat exchanger is the part of a furnace that transfers heat from the flames to the household air.  A functional heat exchanger keeps the household air and the combustion gases completely separate from each other.  If a furnace has a cracked heat exchanger, the combustion gases can mix with the household air.  It’s usually just a little bit, but this is still unacceptable, and it means the furnace or heat exchanger should be replaced.  The photos below show cracks in heat exchangers (click the photos for full-sized images).

Cracked Heat Exchanger #1 Cracked Heat Exchanger #2 Cracked Heat Exchanger #3 Cracked Heat Exchanger #4

False: Cracked heat exchangers can be fixed.  They can’t be fixed.  The heat exchanger or entire furnace needs to be replaced.

False: High CO levels = cracked heat exchanger.  See above.  We test the CO levels in the flue gas, which has nothing to do with a cracked heat exchanger.  Heat exchangers fail when the metal rusts through or when it cracks.  CO does not cause this.

False: High CO levels in the flue gas mean the furnace is leaking CO.  If there is a high level of CO in the flue gas, there is a potential for the exhaust gases to mix with the household air, or ‘leak’.  One way would be for the exhaust gases to backdraft, which means that instead of rising up and out of the house, they come back down the flue.  The other way would be because of a cracked heat exchanger.  If we find high levels of CO in the flue gas, we recommend immediate repair – it doesn’t matter if the gases are mixing with the household air at the time of the inspection or not, because this condition could potentially change at any time.  Higher CO levels can often be fixed.

False: Backdrafting at a furnace or water heater means CO is coming in to the home. Backdrafting means that exhaust gases are spilling back in to the home, rather than going up the flue.  A properly functioning water heater or furnace will not create high levels of CO, so you can’t say CO is coming in to the home unless you test the exhaust gases; we do this at every inspection.  The video below shows me doing this.  While backdrafting doesn’t mean CO is coming in to the home, this is still a potentially hazardous situation that requires immediate correction.  Backdrafting has the potential to allow CO in to the home, and will always contain CO2 (carbon dioxide), which can cause sickness and headaches in higher concentrations.

Wrong Term: Hot water heater.  Just ‘water heater’.  The heated water that comes out is hot.

To summarize, high levels of CO need to be fixed, cracked heat exchangers need replacement, and backdrafting is never ok.  These three things are all independent, but a combination of these conditions is especially dangerous.  When using these terms, make sure you have them correct.  It makes a difference.

Reuben Saltzman, Structure Tech Home Inspections – EmailMinneapolis Home Inspections